I've tried so may ways on the Internet to append a character to a char* but none of them seems to work. Here is one of my incomplete solution:
char* appendCharToCharArray(char * array, char a)
{
char* ret = "";
if (array!="")
{
char * ret = new char[strlen(array) + 1 + 1]; // + 1 char + 1 for null;
strcpy(ret,array);
}
else
{
ret = new char[2];
strcpy(ret,array);
}
ret[strlen(array)] = a; // (1)
ret[strlen(array)+1] = '\0';
return ret;
}
This only works when the passed array is "" (blank inside). Otherwise it doesn't help (and got an error at (1)). Could you guys please help me with this ? Thanks so much in advanced !
The specific problem is that you're declaring a new variable instead of assigning to an existing one:
char * ret = new char[strlen(array) + 1 + 1];
^^^^^^ Remove this
and trying to compare string values by comparing pointers:
if (array!="") // Wrong - compares pointer with address of string literal
if (array[0] == 0) // Better - checks for empty string
although there's no need to make that comparison at all; the first branch will do the right thing whether or not the string is empty.
The more general problem is that you're messing around with nasty, error-prone C-style string manipulation in C++. Use std::string
and it will manage all the memory allocation for you:
std::string appendCharToString(std::string const & s, char a) {
return s + a;
}
char ch = 't';
char chArray[2];
sprintf(chArray, "%c", ch);
char chOutput[10]="tes";
strcat(chOutput, chArray);
cout<<chOutput;
OUTPUT:
test
The function name does not reflect the semantic of the function. In fact you do not append a character. You create a new character array that contains the original array plus the given character. So if you indeed need a function that appends a character to a character array I would write it the following way
bool AppendCharToCharArray( char *array, size_t n, char c )
{
size_t sz = std::strlen( array );
if ( sz + 1 < n )
{
array[sz] = c;
array[sz + 1] = '\0';
}
return ( sz + 1 < n );
}
If you need a function that will contain a copy of the original array plus the given character then it could look the following way
char * CharArrayPlusChar( const char *array, char c )
{
size_t sz = std::strlen( array );
char *s = new char[sz + 2];
std::strcpy( s, array );
s[sz] = c;
s[sz + 1] = '\0';
return ( s );
}
Source: Stackoverflow.com